Sintered cermets are widely used as members requiring wear resistance, sliding properties, or chipping resistance, such as cutting tools, wear-resistant members, and sliding members. In these sintered cermets, developments of novel materials for improving their performance are pursued, and there are attempts to improve their characteristics.
For example, patent document 1 discloses that wear resistance, chipping resistance, and thermal shock resistance are improved by setting the value of the crystal lattice constant of a binder phase constituting the surface of a cermet cutting tool to be not less than 0.01 angstrom smaller than the value of crystal lattice constant of a binder phase constituting the interior of the cermet cutting tool.
Patent document 2 discloses a sintered cermet including a hard phase composed mainly of Ti, and a binder phase composed of an iron-group metal, and having three or more kinds of B1 type crystals in which their respective peak positions of the (113) plane in X-ray diffraction analysis are spaced 0.2 to 1.0 degree apart.
Patent document 3 discloses a sintered cermet in which in peaks of a large strength detected on a low angle side among peaks indicating a hard phase in X-ray diffraction analysis, the half width of a peak measured in the surface part of the sintered cermet is 40 to 60% of the X-ray diffraction peak of the interior thereof. FIGS. 3 and 4 illustrate the sintered cermet in which one peak of the (113) plane is detected in the surface part thereof, and two peaks of the (113) plane are detected in the interior thereof.